Methods for multiple media digital communication

ABSTRACT

Methods for media communication in a digital communication system. In one embodiment, the media comprises a plurality of media types (including for example audio, video, and/or data packets), and the system includes a processing apparatus for establishing communication between first and second callers over respective first and second communication mediums, which include one or more packet-switched communication channels. The method comprises using a connection routine of the processing apparatus to enable media type selections by the callers, and transmitting, via the processing apparatus, a plurality of media packets corresponding to each of the selected media types.

This application is a continuation of application Ser. No. 09/596,835 filed Jun. 19, 2000 now U.S. Pat. No. 6,738,357 of the same title, which is a continuation of prior application Ser. No. 09/437,269, filed Nov. 10, 1999, now U.S. Pat. No. 6,104,706, which is a continuation of Ser. No. 08/795,798, filed Feb. 5, 1997, now U.S. Pat. No. 5,995,491, which is a continuation of Ser. No. 08/626,580, filed Apr. 2, 1996, now U.S. Pat. No. 5,623,490, which is a continuation of Ser. No. 08/073,956, filed Jun. 9, 1993, now abandoned.

FIELD OF THE INVENTION

The present invention relates to the field of digital communications systems, and more particularly to systems transporting multiple media (multimedia) and/or communicating such multimedia through a plurality of connections to multiple callers.

BACKGROUND OF THE INVENTION

In the prior art, multimedia communications, such as video conferencing systems for providing two way video and audio, are well known. Given sufficient bandwidth and dedicated independent channels, (e.g. 6 Mhz for an analog video channel, 3 Khz for an audio link over a standard analog telephone line, etc), video conferencing between two callers can be realized. However, communication channels providing 6 Mhz video bandwidth are not generally or universally available. A major obstacle to wide spread implementation and acceptance of multiple media conferencing systems is the limited bandwidth of the available communication channels. In addition, typical communication channels available on packet switched networks such as AppleTalk, from Apple Computer, California, USA, or Netware from Novell Inc, Oregon, USA, do not provide the continuous real time analog or digital connection of a telephone line or modem. Instead, packet switched networks provide non-real time bursts of data in the form of a switched packet containing a burst of digital data. Thus, in addition to bandwidth limitations, packet switched networks present delay limitations in implementing real time multiple media conferencing systems. The same bandwidth and time delay limitations which apply to all time division multiple access (TDMA) communication systems and similar schemes present obstacles to achieving real time multimedia communications.

Typically, the problem of video conferencing two callers is approached by compressing the composite video signal so that the resulting transmitted data rate is compatible with the available communication channel, while permitting acceptable video and audio to be received at the other end of the communication channel. However, solutions in the past using lossy compression techniques, have been limited to compromising quality in order to obtain acceptable speed. Recently, non-lossy compression techniques have become available. The problem still remains as to how to match the bandwidth and timing constraints of available digital formats to the available communication channels, both present and future.

SUMMARY OF THE INVENTION

The present invention is embodied in a digital communication system where multiple media data sources are time multiplexed into a packetized data stream. At both the transmit side, and the receive side, audio packets are given priority processing over video packets, which in turn have priority over text/graphics data packets. Continuous real time audio playback is maintained at the receiver by delaying the playback of received audio in a first in/first out (FIFO) buffer providing a delay at least equal to the predicted average packet delay for the communication system. Optionally, the average system delay is continuously monitored, and the audio and video playback delay time as well as audio and video qualities are adjusted accordingly. In another embodiment of the invention, a conference of three or more callers is created by broadcasting a common packetized data stream to all conference callers. Use of the present invention further permits an all software implementation of a multimedia system.

1. In accordance with a first aspect of the present invention, multiple data sources forming data packets are combined into a prioritized data stream.

The present invention is embodied in a method and apparatus for combining data from a plurality of media sources into a composite data stream capable of supporting simultaneous transmission including multiple video and graphic signals and real time audio. Video, audio and other signals are integrated in a non-standard transmission format determined by a novel streaming algorithm and prioritization scheme designed to provide the best balance between transmission quality and realization of real time rendition of each.

For example, each data type packet at the transmitter is assigned a priority between 0 and 10000, with 0 being the highest priority and 10000 the lowest. An audio packet is given priority 20, a video packet is given priority 50. Screen data packets and file data transfer packets are both given priority 180.

Before transmission on the communication channel, packets are placed in a queue according to priority order. As new packets are generated, the queue is reorganized so that the new packet is placed into its proper priority order.

At the receiver, each task runs according to its assigned priority. Packets with priorities between 0 and 100 are processed first, to the exclusion of packets with priorities 101 through 10000. Audio, being the highest priority (20), is processed first to the exclusion of all other packets. Within the class of packets with priorities between 101 and 10000, packets are processed according to relative priority. That is, higher priority tasks do not completely shut out tasks of lower priority. The relationship among priorities is that a priority 200 task runs half as often as a priority 100 task. Conversely, a priority 100 task runs twice as often as priority 200 task. Tasks with priorities between 0 and 100 always run until completion. Thus, video, screen data and file data, processing tasks are completed after audio processing in accordance with the relative priority of the packets.

A multi-tasking executive dynamically reassigns task priorities, to efficiently complete all tasks within the available time, while performing the highest priority tasks first. At any given time, there are different tasks all at different priorities, all yielding to each other. In general, a task yields to a higher priority task, if it is not running an uninterruptable sequence. If the current task completes its cycle, its priority is reassigned to a lower priority. If the priority of two or more tasks is equal, then the multi-tasking executive executes each task in a round robin fashion, performing a portion of each task, until the completion of all tasks with the same priority.

The assignment of packet priorities, and processing according to priority assures that audio will be given precedent over video, while audio and video will be given precedent over both screen data and file transfer data.

As indicated above, continuous real time audio playback is maintained at the receiver by delaying the playback of received audio in a first in/first out (FIFO) buffer having a size at least equal to the predicted average packet delay for the communication system. Optionally, the delay of the audio FIFO may be made variable. A variable delay audio FIFO buffer at the receiver allows the system to shrink or grow the time delay between one machine and the other. The ability to shrink or grow the difference in time between the sender and receiver permits the system of the present invention to compensate for indeterminate system delays. If the changes are slight, the difference in pitch is not noticeable. For greater changes, the technique of audio resampling may be used to increase or decrease the rate of audio playback without changing the pitch of audio content.

Similarly, video playback continuity at the receiver may also be improved by delaying the playback of received video in a first in/first out (FIFO) buffer having a size at least equal to the predicted average packet delay for the communication system. The delay of the video FIFO may be made variable, allowing the system to shrink or grow the time delay between one machine and the other to compensate for indeterminate system delays. Again, if the changes are slight, the change in frame rate is not noticeable. However, video data does not age as quickly as audio data. Therefore a smaller video FIFO can be used. Also, a video image may have short discontinuities without a perceived loss of the video connection. Audio playback, on the other hand, is more sensitive to discontinuities, and it is more important to maintain continuity at the receiver. Ideally, when both audio and video are used in a multimedia conference, the delay for audio and video should be equal to make sure that they are synchronized. In the latter case, the actual system delay is calculated by finding the maximum delay of both audio and video packets.

Data from media sources tend to come in bursts. For example, audio data rates rise when speaking, and fall to zero during a silence. In the present embodiment, the silence between words provides the present system with an opportunity to catch up by refilling the audio FIFO buffer before it empties. In such manner, the present system compensates for the delay inherent in a packet switched, time delay variant, communication channel.

Similarly, video sources including graphic screen data, are generated in bursts. That is, the data rate for video ideally falls to zero when there is no motion. The data rate for transmitting screen graphics falls to zero when are no changes. When the caller changes the screen, (such as the collaborative work document displayed on the screen), data is generated.

Thus, following the priority scheme of the present invention, video is updated only when no speech data is being processed. However, processing of speech data does not included the playing of sound. Once the sound starts playing, there is no need to further spend time to process the sound. Sound playing needs no supervision. Therefore, video updating occurs while sound is playing. After speech is playing close to real time (with a delay), video text and graphics are updated in the background. Video, text, graphics and data files are updated at lesser priorities. Except for audio and video data, task priorities are re-assigned to assure that all tasks will be completed, and that a higher priority task will not completely prevent the lower priority tasks from being completed.

2. In accordance with a second aspect of the present invention, multiple signal packets are broadcast to a plurality of callers to create a common multimedia conference.

In addition to assigned priorities, data packets having multiple destination addresses are broadcast over a plurality of connections to multiple callers. Each caller receives the same data packets with assigned priorities, and processes the received packets in a similar manner. As new data is generated from each caller in the video conference, new data packets are broadcast to the other callers. Thus, due to the broadcast of data packets representing audio, video and screen data, all callers are conferenced together, each seeing and hearing each other, while discussing the same screen document. Additional callers can be added to the conference over a plurality of connections without adding undue burden, because in a conference, each caller needs to generate data only once, which is then transimtted either simultaneously or sequentially depending on the kind of connection, to other callers.

3. In accordance with a third aspect of the present invention data received on a first communication medium (for example on a broadband local area network, such as ethernet) are re-broadcast on a different communication medium (such as a telephone line) in order to conference callers on the different communication media in a common multimedia conference. The present invention thereby provides the option of desktop video conferencing on standard computer networks and telephone lines.

4. In accordance with a fourth aspect of the present invention, a method for use in a communications network is disclosed. In one embodiment, a processing machine establishes communications between at least first and second user machines, the first user machine being coupled to the processing machine over a first communication medium, and the processing machine being coupled to the second user machine over a second communication medium, and the method comprises: causing signals to be sent to the first and second user machines to enable media type selections, at least one of the media type selections including a selection of at least two different media types; and transmitting via the processing machine a plurality of digital media packets corresponding to the at least two different media types, the digital media packets being transmitted in accordance with the media type selections over the first communication medium.

In one variant, the first communication medium comprises a packet switched network, and the second communication medium comprises, e.g., a non-packet switched network.

In another embodiment, the method comprises: causing control signals to be sent to at least one of the first and second users to enable respective media type selections; and transmitting via the processing machine and a packet-switched network a plurality of digital media packets corresponding to each of at least two different first user media types, the at least two different first user media types being selected based at least in part on the control signals. For at least one of the at least two different first user media types, the first processing machine further causes signals associated with at least a portion of the plurality of digital media packets to be delivered to at least the second user consistent with the second user media type selection.

In yet another embodiment, the communications network comprises a first processing machine that establishes communication between at least second and third processing machines, the second processing machine being in communication with the first processing machine via communications channels of a packet-switched network having indeterminate packet loss. The first processing machine being in signal communication with the third processing machine via at least a non-packet switched network, and the method comprises: causing signals to be sent to the second and third processing machines to enable media type selections; and transmitting via the first processing machine and the communications channels a plurality of digital media packets corresponding to each of at least two different media types selected via the second processing machine based at least in part on the signals. For at least one of the at least two different media types, the first processing machine further causes signals related to at least a portion of the transmitted digital media packets to be delivered to at least the third processing machine consistent with the third processing machine's media type selection.

5. In accordance with a fifth aspect of the present invention, a method of communication is disclosed. In one embodiment, the method is adapted for use in an apparatus adapted to couple into communication a remote processing machine with a caller coupled via a telephone line, and comprises: negotiating with the remote processing machine a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to the selection, the apparatus to process media data packets received from and to be transmitted to the remote processing machine over a packet switched network via one or more packet switched communication channels; and placing the caller into signal communication with the apparatus at least via the telephone line. In one variant, the one or more packet switched communication channels have an indeterminate packet loss, and the media type selection is of only audio. The negotiation comprises sending a first message and receiving a response message, and involves a message format that supports the description of the audio, video and data media types. The apparatus communicates information between the remote processing machine and the telephone line.

6. In accordance with a sixth aspect of the present invention, a method of communication over a network is disclosed. In one embodiment, the network comprises a processing machine that establishes communication between a first caller and a second caller, the first caller being coupled to the processing machine over a first communication medium, the processing machine being coupled to the second caller over a second communication medium, and the method comprises: invoking at least one connection routine at the processing machine to cause control signals to be sent to at least one of the first and second callers to enable media type selections, at least one of the media type selections including a selection of at least two different media types; and transmitting via the processing machine a plurality of digital media packets corresponding to each of the at least two different media types. For at least one of the at least two different media types, at least a portion of the plurality of corresponding digital media packets are transmitted to at least one of the first and second callers in accordance with the media type selections, over the first communication medium via one or more packet switched communication channels. The one or more packet switched communication channels include a single connection stream that includes packets of at least one media stream set up for each of the at least one media type by the first and second callers.

7. In accordance with a seventh aspect of the present invention, a method of transmitting data packets from a first processing machine to be delivered to one or more of a plurality of remote processing machines in data communication therewith, is disclosed. In one embodiment, the method also places a telephone subscriber into communication with the plurality of remote processing machines, and comprises: transmitting a plurality of media data packets for delivery to at least one of the plurality of remote processing machines over a packet switched network via one or more packet switched communication channels, wherein each of the media data packets has a plurality of data fields associated therewith, at least one of the data fields comprising at least one destination address associated with a respective one of the plurality of remote processing machines; and communicating signals of at least one media type via a telephone network to couple the telephone subscriber into communication with the plurality of remote processing machines. A first number of the plurality of media data packets may be transmitted for delivery to a first subset of the plurality of remote processing machines while a second number of the plurality of media data packets may be transmitted for delivery to a second subset of the plurality of remote processing machines, the first and second subsets not being identical.

These and other aspects of the invention are now described in detail herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a dialog box indicating connection status as it would appear on the screen of a Macintosh computer used in conjunction with the present invention.

FIG. 1B is a dialog box indicating an incoming call as it would appear on the screen of a Macintosh computer used in conjunction with the present invention.

FIG. 1C is a dialog box illustrating the connection status message that would appear for a call that was not accepted as it would appear on the screen of a Macintosh computer used in conjunction with the present invention.

FIG. 1D is a window containing a moving video image as it would appear on the screen of a Macintosh computer used in conjunction with the present invention.

FIG. 2 is a video screen illustrating a video conference between two callers and sharing a common document.

FIG. 3 is a video screen illustrating a video conference between three callers and sharing a common document.

FIG. 4 is a block diagram illustrating the sequence of operations for establishing a connection in a multiple media digital communication system embodying the present invention.

FIG. 5 is a block diagram illustrating the sequence of operations for establishing media types to be used in a conference call in a multiple media digital communication system embodying the present invention.

FIG. 6 is an illustration of a packet data format used in conjunction with the present invention.

FIG. 7A is a block diagram of a multiple media communication system transmitter in accordance with the present invention.

FIG. 7B is a block diagram of a multiple media communication system receiver in accordance with the present invention.

FIG. 8 is a block diagram of a method and apparatus for processing a data packet in accordance with the present invention.

FIG. 9 is a block diagram illustrating the sequence of operation of a method and apparatus for processing data packets in accordance with the present invention.

FIG. 10 is a block diagram of a method and apparatus for establishing a connection for specific media between callers used in conjunction with the present invention.

FIG. 11 is a block diagram illustrating the sequence of data packet flows with optional acknowledgement handshake packets.

FIG. 12 is a block diagram of a multiple media digital communications system for sending and receiving multiple media for a first caller in accordance with the present invention.

FIG. 13 is a block diagram of a multiple media digital communications system for receiving and sending multiple media for a second caller in accordance with the present invention.

FIG. 14 is a first configuration of the present invention for conducting a standard videoconference call over an ethernet network.

FIG. 15 is an alternate configuration of the present invention for conducting a standard videoconference call with collaborative data over an ethernet network.

FIG. 16 is an alternate configuration of the present invention for leaving a recorded multimedia message of a videoconference call with collaborative data over an ethernet network.

FIG. 17 is a three caller multimedia conference call in a system in accordance with the present invention.

FIG. 18 is an alternate embodiment of a three caller multimedia conference call in a system using both ethernet and a telephone modem in accordance with the present invention.

DETAILED DESCRIPTION

From the viewpoint of the caller, the present multimedia communication system operates as follows:

A caller on a desktop computer initiates a multimedia call by selecting a media type and desired connection with a second party. A dialog box of the type shown in FIG. 1A appears on the screen, illustrating the connection status. Caller 2, who receives the call, views a dialog box on his screen of the type illustrated in FIG. 1B to announce an arriving call. Caller 2 has the option of deciding to either pick up or deny the call, or to take a message. If the call is denied by caller 2, then caller 1 views a dialog box 14 as illustrated in FIG. 1C. For purposes of illustration, a video box 16 containing a video of the first caller 1 is shown in FIG. 1D. If the caller decides to take a message, caller 2 can now control the connection and optionally send an announcement message requesting a message.

FIG. 2 illustrates the screen appearance of a typical multimedia call with a collaborative document. On the screen 20 of caller 1, a video box 24 appears in which a moving video showing caller 2 appears. The screen of caller 2 is similar, but contains the image and sound of caller 1. On both the screens of callers 1 and 2 can be a collaborative document 22. Caller 1 and caller 2 are connected by moving video and two way audio and can discuss collaborative document. Caller 1 may manipulate the document and the changes will appear on the screen of caller 2. In an alternate embodiment, caller 2 may manipulate the document as well.

FIG. 3 illustrates the screen 20 appearance of a three party video conference as it appears to caller 1. Caller 3 appears in a video box 26 as well as caller 2 in another video box 26, and the collaborative document 22. The other callers 2 and 3 see the other two members of their video conference on their screen as well as collaborative document 22. The size and position of video boxes 24 and 26 is selectable by caller 1. A video image 25 of caller 1 may also appear on the screen of caller 1 to let caller 1 see what is being transmitted. Reducing the size of video box 25 reduces the amount of (video) data which must be transmitted by the communication system.

Connection Establishment

The sequence of operation for establishing a connection between caller 1 and caller 2 over a communication network is illustrated in FIG. 4. The network may typically be AppleTalk, ethernet or any other commonly available local area network. Also, a connection can be established over a telephone line or other proprietay digital telephone lines such as ISDN.

The terms, “connection stream” and “media stream” used below are further defined in the description of FIGS. 8–11. For present purposes, such terms may be regarded as routines for handling data packets. Caller 1 selects a media type stream 28, and a connection stream 30, suitable for the communication medium. An initial message termed a helo packet is sent to a caller 2 connection stream 32. The connection stream 32 provides a dialog box to caller 2 informing that there is an incoming call from caller 1. Caller 2 can then decide 34 to either accept or deny the call, or alternatively to take a message if caller 2 is not present. The accept, deny and take commands are communicated back to the connection stream 32 which sends a return message across the communication system back to connection stream 30 and caller 1.

In addition to denying or taking the call, caller 2 has the option to pick a different media type. That is, for example, if the media type stream 28 of caller 1 is video, and caller 2 does not want to accept a video call but will accept an audio call, then the return message pick will indicate that caller 2 is picking audio as the media for an incoming call. At caller 1, connection stream 30 distributes the response from caller 2. Specifically, if the call is denied then the connection attempt is deleted 40. If a different media is picked, then a modification of the media type stream 28 is performed. If take a message was selected, then the appropriate file transfer 38 takes place to transmit an announcement file, and a message is requested to be sent back.

FIG. 5 illustrates the communication sequence for selecting the among the various media types between caller 1 and caller 2. For media type stream 42, a request is sent through connection stream 44 across the communication channel to caller 2 at connection stream 46 which is forwarded to media type stream 48. Caller 2 configures itself to accept the media type stream which is being presented to it by modification of its registration server 50 which clones the desired media type. If accepted, media type stream 48 sends a message through connection stream 46 across the communication medium to caller 1. The acceptance is received at connection stream 44 and communicated to media type stream 42 which opens up the connection for the given media type between caller 1 and caller 2.

Data Format in Packets with Priority and Multiple Destinations

FIG. 6 shows a packet data format 52 suitable for use in conjunction with the present invention. The length of the packet is Indicated by data field 54. The length of the header is indicated by data field 56. The packet type and identification are respectively indicated by data fields 58 and 60.

The priority of the data packet is indicated in data field 62. When transporting multiple media digital data packets, the priority data field determines which of the packets has the highest priority in processing. Data fields 64 and 66 respectively contain information as to the message state, and a checksum for determining message errors. The packet source address is indicated at data field 68, and a destination count as to the number of destinations this packet will reach is indicated at data field 70. Also, an active destination count, the number of destination which have not yet received this packet, and a maximum destination count is provided in data fields 72 and 74 respectively.

The data packet 52 of FIG. 6 contains a number of destination addresses 76. The plural destination addresses provides a broadcast capability by which all the callers in a conference call can view common documents and see and hear each other. That is, when a data packet 52 contains audio data representing one speaker's voice, that packet is broadcast to all the destinations simultaneously. The same is true of the video and document updates. The destination addresses is followed by the actual variable length data of the data packet in field 78.

System Overview

A block diagram of a multiple media communication system transmitter is shown in FIG. 7A. A packet with priority 20 is generated 708 from audio data source 702. A packet with priority 50 is generated 710 from video data source 704. A packet with priority 180 is generated 712 from text/graphics data source 706. A WriteQueue 716 (a buffer memory for storing packets to be sent) is provided for holding packets to be transmitted over the communication channel 718. Control 714, responsive to packet generation, 708, 710, 712 places the packets in the WriteQueue 716 in order of packet priority. In hardware, a queue maybe a FIFO. In software, WriteQueue 716 is a linked list of packet containers with pointers to the next and previous packet containers. Since the Writequeue 716 is an ordered list, adding a new entry is achieved by modifying two pointers to add the new entry to the list in the proper order.

A block diagram of a multiple media communication system receiver is shown in FIG. 7B. Two substantially similar receivers, one for caller 2 and another for caller 3 are illustrated. Both callers are respectively connected to a broadcast communication channel 720, 746. A ReadQueue 722, 724 (a buffer memory for storing packets) receives packets for processing. A control means 726, 728 selects packets to be processed based on the packet priority. A multi-tasking control 730, 738 processes data-packets in accordance with assigned priorities. As indicated, audio packets have the highest priority and are processed first. Other packets are processed in accordance with priority in a multi-tasking environment which balances speed of execution among the different priority packets while making sure to complete all tasks. A variety of multi-tasking control techniques for completing multiple tasks simultaneously, giving priority to higher tasks, while devoting some system resources to complete the lowest priority tasks, are known to those skilled in the art.

Audio data playback is delayed in a delay 734, 742, as indicated above. Video data display is similarly delayed in delay 731, 739 to maintain synchronism between video and audio. The multi-task control 730, 738 sets the amount of delay (for both video and audio) in accordance with the predicted average delay of the communication channel 720, 746. Delayed audio is then displayed 736, 744 at the receiver for caller 2 and caller 3. Delayed video is simultaneous displayed 732, 740 at the receiver for caller 2 and caller 3. Furthermore, since callers 2 and 3 are both receiving the same packets broadcast by caller 1, both hear and view the same multimedia messages.

Multimedia communication is typically two way between all callers. It should be understood that caller 1, caller 2 and caller 3 all include the transmitter and receiver elements shown in FIGS. 7A and 7B. This does not mean, however, that all callers need to transmit or receive data. Each caller can choose to (or be required to) receive only or transmit only.

In operation, at caller 1 in FIG. 7A, successive multimedia data packets with assigned priority are generated 708, 710, 712 from respective multimedia sources 702, 704 and 706. As the packets are generated, each is placed 714 in priority order in a queue 716 and transmitted over a communication channel 718. If the channel capacity were unlimited, packets would be transmitted as soon as generated. However, in the normal case, generated packets may accumulate awaiting transmission because the communication channel capacity is limited. The present priority scheme assures that packets are transmitted in priority order with the highest priority packets transmitted first.

At the receiver, callers 2 and 3 in FIG. 7B both receive packets from the communication channel 720, 746. Received packets at callers 1 and 2, are processed in accordance with the received priority, to play back the received audio, video and display of the received text/graphics. Since both callers 2 and 3 receive the same packets, a three party videoconference call is created.

Continuity of audio playback is perceived as critical to a multimedia conference. Accordingly, audio packets, being assigned the highest priority, are sent as soon as possible, and at the receiver, are processed as soon as possible after receipt. Thus, audio packets tend to be delivered in the shortest time which the communication channel will allow.

The system of the present invention tolerates transmission errors inherent in a traditional packet switched system by discarding or retransmitting corrupted audio or video. For text files, the normal error detection and retransmission requests are used. Sound and video are distinguished from text or file data in that it is possible to tolerate some loss of sound and video and still maintain an acceptable quality. In the event of a detected error in the received audio or video packet, the receiver determines whether there is sufficient time to flag the error and request a retransmission, based on the predicted average delay time of the system. If there is not sufficient time, the corrupted packet is ignored. In such manner, network capacity is not wasted on retransmissions which will arrive too late and have to be discarded anyway. However, the lowest priority packets of text/graphics or computer file data which are not time dependent, are flagged for errors and retransmitted.

Object Oriented CPacketStream Streaming Method

Various types of streams are used to achieve multimedia communications. First, a connection stream provides the interface to the communication channel. Then, there is a media stream for each desired media. For example, there may be a video stream, an audio stream, a video and audio stream such as QuickTime, or a text/data/graphics stream representing files, graphic images of many types, or any other data required. The architecture is designed to support “drop in” streams for new kinds of collaborative data.

The block diagram of FIG. 8 illustrates the method and apparatus for sending and receiving data packets, also termed CPackets. Each of the above methods and tasks is described in detail below, including pseudo code for realizing each of the methods and tasks on a general purpose digital computer. Although the preferred embodiment is described in terms of software operating in a Macintosh computer environment, it will be understood that the present multiple media communication system of the present invention may be implemented in hardware, such as in dedicated logic, microprogrammed bit slices, programmable arrays and the like.

CPacketStream 80 is a software component which is responsible for handling CPackets to establish communication channels between machines. Each CPacketStream 80 is composed of a set of routines (or methods) responsible to interact with CPackets. These methods are used in turn by a set of tasks running in each CPacketStream. The task types and methods (or routines) available for packet handling are summarized as follows and described in more detail below.

Tasks:

WriteTask (prioritized multi-tasking of received CPackets) ReadTask (connection stream distributes received CPackets) IdleTask (send final packet and initial packet) OpenTask (open connection stream) Methods

DoQueue (puts a Cpacket in the WriteQueue) DoWrite (generates actual output from packet data) DoIdle (idle between packets) Write (lookups destination and calls DoQueue) WriteDone (acknowledges receipt of packet) WriteQueue (A buffer containing CPackets in priority order) ReadQueue (A buffer containing CPackets in received order) CPacketStream::WriteTask 94

The WriteTask 94 is responsible for distributing packets contained in the WriteQueue 96 in each CPacketStream 80. The priority of this task is at least as high as the packet it is currently handling. This task is in a loop currently scanning the WriteQueue 96, if the queue is empty then the task will sleep. The CPacketStream::DoQueue method will put a CPacket into the WriteQueue 96, and wake the WriteTask 94 up. Therefore, the WriteTask 94 will be the one displaying or playing the packets.

CPacketStream::WriteTask  if a packet in WriteQueue   call DoWrite for that packet to handle data  end end CPacketStream::ReadTask 82

The ReadTask 84 is responsible for reading CPackets from a particular channel, and redistributing among CPacketStreams 80 in that machine. This type of task is only appropriate for a connection (media) CPacketStream 80. (In a way it is similar to the WriteTask 94, serving a WriteQueue 96, but in the reverse direction, and corresponding to receiving data packets in a ReadQueue)

CPacketStream::ReadTask  if a new packet read   write a new packet  end end CPacketStream::IdleTask 82

The idle task 82 is responsible for generating and sending ‘helo’ (the initial packet) and ‘kiss’ (the final packet) CPackets. It is also responsible to execute idle time events in some particular streams. For example, a Communications Tool (from Apple Computer) needs to have an idle call every so often in order to handle a particular connection.

CPacketStream::IdleTask  if initial packet not sent   if initial packet not created    create initial packet   end   sent initial packet  end  idle stream if necessary  if stream should die    if final packet not created    create final packet   end   send final packet  end  if final packet sent and stream should die    disable and delete the streams  end end

An OpenTask 88 is used when the connection is being first opened and the connection negotiated between callers. At that time, the contents of the table lookup 98, which defines media types and connection streams is determined. In addition to these tasks, there are several methods that are called by these tasks in order to communicate with the stream. These methods are:

CPacketStream::DoQueue 86

This is the method that is called in order to give a packet to a particular stream. Most streams will immediately write the packet to a WriteQueue 96, and activate the WriteTask 94 in order to handle that particular packet.

CPacketStream::DoQueue 86  put packet into the write queue  wakeup WriteTask end CPacketStream::DoWrite 92

The WriteTask 94 will call this routine to actually handle the packet's content. For a connection stream, this is the output routine of a CPacketStream 80 to the communication channel. For a video stream, this routine will decompress and display the video contained in a packet. For other media streams, the DoWrite 92 routine will carry out the appropriate process to get the data displayed, played or otherwise.

CPacketStream::DoWrite  handle the packet's data end CPacketStream::DoIdle

This is the routine which can be used to idle the CPacketStream 80. Many streams can use this to do periodic tasks.

CPacketStream::DoIdle  perform periodic task end CPacketStream::Write 90

This routine will look up in table 98 the destination address for each destination in the packet, and the call DoQueue 86 for each destination packet stream. Each DoQueue 86 can refuse the packet until a later time, and therefore the packet contains flags for each destination address such that a complete write will mark that address completely written. A packet therefore contains an active destination count (72 in FIG. 6).

CPacketStream::Write  for all destination addresses in packet   lookup destination stream in address table   if alias entry and ‘info’ packet    add writeAsRemoteInfo flag   end   if found    call DoQueue method for destination stream    if successful     mark destination address write complete    end   else    mark destination address write deleted   end  end end

Data packet flow and handling through CPacketStream 80 is from calls to DoQueue 86 which will write a CPacket into the WriteQueue 96, and then activate WriteTask 94, which processes the Cpackets, and calls DoWrite 92 to distribute the Cpackets contained in the WriteQueue 96.

CPacketStream::WriteDone

This routine will be called to dispose of the packet generated by a certain stream. It can be used for synchronization. A connection stream has the option of calling WriteDone to transfer acknowledge packets on the outgoing connection. The CPacketStream owns the packet which it sends, until all other streams are done with the packet. At that time, the packet ready to be deleted. However, when a packet (e.g., video) is sent from one machine on to another machine, such as between an ethernet LAN (local area network) and a telephone modem, the packet (e.g., the video) is not actually being used. In such circumstances, the originating connection stream should hold the packet, until all other connections have used this packet on the other machine(s). Synchronization of packet receipt is accomplished by returning an acknowledge packet when the WriteDone function of the connection stream is called at each machine which receives the packet. This is an additional form of communications between machines to reinforce the normal packet communications. “Acknowledge” packets have the same priority as the information packets, the lowest packet priority.

Streaming Algorithm

A generalized representation of the use of the present streaming algorithm is shown in the block diagram of FIG. 9. Two CPacketStreams, CPacketStream A, 801 and CPacketStream B, 802 are shown. By way of example, if CPacketStream A was a connection stream, then CPacketStream B would be a media stream, such as a video stream. On the other hand if CPacketStream A was a video stream, such as from a frame grabber, then CPacketStream B would be a connection stream. In general, there is one stream for each type of media, plus one stream for each connection. That is, a separate connection stream is used for each caller. Thus, for a two way conference with one other caller, there is one connection stream, while for a three way conference there are two connection streams, one for each of the other two callers. In an alternate embodiment, such as may be used with future higher speed communication systems, a single connection stream may be used with more than one caller.

FIG. 9 also shows a lookup table 818 which is filled in when each stream is established for keeping track of the destination of the various packets. In operation, a packet is generated 804 and the Write function 806 is called. The pseudo code 816 for the write function 806 contains a reference to a lookup to table 818, which returns an address to CPacketStream B, 802. CPacketStream B, 802 calls DoQueue 812, which writes the CPacket to WriteQueue 810. WriteTask 814 is activated to process the CPacket, which calls DoWrite 808 to generate the output routine of a CPacketStream 80 to the communication channel, or other appropriate media output.

FIG. 10 illustrates the use of lookup tables to generate destination addresses from connection information between two given callers. By way of example, assume that CPacketStream A, 904 is a video stream connected to frame grabber 902 and image decompressor 912 at machine 1. A machine 2, CPacketStream D, 910 is also a video stream connected to a frame grabber 920 and image decompressor 918 at machine 2. Then, CPacketStream B, 906 is a connection stream coupled to a communication channel interface 914, such as for example a transmission source for an AppleTalk Data Streaming Protocol (ADSP) device. CPacketStream C, 908 is a connection stream coupled to a communication channel interface 916, shown as the receiving side of an AppleTalk Data Streaming Protocol device. Machine 1 uses table 922 to lookup the destination stream address 2,D for packets generated using data from video grabber 902. Similarly, machine 2 uses lookup table 925 to lookup the destination stream address 1,A for packets generated using data from video grabber 920.

Packet Acknowledgement

A block diagram illustrating the use of an optional acknowledgement packet is shown in FIG. 11. A media stream 928, responsive to a video packet 936, calls the Write function, which through the appropriate lookup table, calls the DoQueue and DoWrite functions of connection stream 930, an ethernet connection stream. The video packet is transmitted on the ethernet communication channel 938 and received by the ReadTask and Write functions of connection stream 932. Thereafter, the DoQueue and DoWrite functions of media stream 934 are called through the appropriate lookup table which displays the data on video display 940.

The communication channel LAN protocol typically supports lower level acknowledgment functions. For example, it is known by the transmitting caller that the packet was received over the clear communication channel 938. Otherwise, the LAN protocol (at the ADSP level for example) would have returned an error indication. In addition to the acknowledge at the LAN protocol level, an acknowledge packet is generated when the received data is played (i.e., when the video data is displayed) in order to provide end to end synchronization information. The WriteDone function of connection stream 932 generates such acknowledge packet for return transmission across communication channel 938. Back at the originating transmitting caller, the ReadTask function of connection stream 930, calls WriteDone routine of media stream 928 to process the acknowledge packet. The receipt of an acknowledge packet also provides an indication of system delay for the media type of media stream 928, in this example, a video packet. The acknowledge packet contains a recorded time indicating when the video packet was actually used. Comparison of the recorded transmission time with the received recorded display time, provides a measure of the end to end system delay.

Prioritized Data Packet Processing

A system block diagram is illustrated in FIGS. 12 and 13. FIG. 12 shows the transmission elements in solid lines and the receive elements in dotted lines. FIG. 13 shows the receive elements in solid lines and the transmit elements in doted lines.

In FIG. 12, and audio data source 110 and video data source 112 are coupled through audio/video stream 114 and connection stream 116 to data communication channel 118. In FIG. 13, data communication channel 118 is coupled to connection stream 216, and then to audio/video stream 214. Audio is played by sound manager 220, which includes a FIFO delay buffer 228. Video is played back by video decompressor 224 coupled to video display device 226.

For the return direction, FIG. 13 also shows audio data source 210 and video data source 212, coupled to the communication channel 218 through audio/video stream 214 and connection stream 216. At the transmission side in FIG. 12, audio is played by sound manager 120, which includes a FIFO delay buffer 128. Video is played back by video decompressor 124 coupled to video display device 126.

In operation in FIG. 12, data generated by audio source 110 and video data source 112 are placed into packets in audio/video stream 114, and forwarded to connection stream 116. The connection stream arranges the available packets in priority order before transmission on the network communication channel 118. Once transmission of a packet has begun, however, it is typically not interruptable. For example, if a video packet represents a video frame update, and the video packet transmission has started, no audio packet can be sent until the current packet is completed. If it is desired to improve audio transfer, the video frame update may be divided into smaller sub-frame packets. Then, an audio packet will be inserted during transmission of a complete video frame update, i.e., by insertion between sub-frame packets forming the video frame update.

In FIG. 13, data packets received by connection stream 216 are distributed to the audio/video stream 214. Audio data packets, having a higher priority represent a higher priority task. Thus, the sound manager 222 is given priority over the video decompressor 224. As indicated above, delay buffer 228 is set equal to the predicted average packet transmission delay of the communication system. Alternatively, the delay provided by delay buffer 228 is dynamically adjustable according to system delay as measured by time reported by return message packets or acknowledge packets. Audio playback is slowed or accelerated in order to shrink or grow the difference in time between the sender and receiver.

Additional media types, such as file text or screen documents may be added to the block diagrams of FIGS. 12 and 13 as additional inputs to the Write function of stream 114 in FIG. 12 and additional outputs of stream 214 in FIG. 13. In sharing collaborative documents, one member of the conference may be running the application such as a word processor or spreadsheet, and the others viewing a screen only. Alternatively, one member of the conference may be running the application, but the keystrokes of the others are transmitted back to the one member as text data. In such manner, conference members may each have direct input into the collaborative application.

As indicated, the preferred embodiment of the present invention is in software running on a Macintosh computer. A software embodiment has the advantage of being hardware independent, capable of working with any available media source, and across any available communication system. In addition, CPacketStream tasks and methods are shared by various connection streams and media streams. It is noteworthy that the present system achieves multimedia conferencing in a uniprocessor architecture.

Alternative embodiments of the present multimedia communication system include multi-processor architectures where the multi-tasking of received multimedia data packets may be replaced by parallel processing, or in special purpose hardware. In dedicated hardware, each CPacketStream could be a special purpose microprogrammed integrated circuit, where one chip would be required for each media type, and for each connection.

FIGS. 14 through 18 illustrate the various capabilities of the present system of multiple media digital communication. FIG. 14 illustrates a standard video call of the type shown in FIG. 2 over an ethernet network of the type illustrated. FIG. 15 illustrates a video call with collaborative data over an ethernet network of the type illustrated on the screen in FIG. 3. This configuration is contemplated as the most common type of multimedia call.

FIG. 16 illustrates a one way video/audio call with collaborative data over an ethernet network. The data is one way because first party did not answer, but that party was configured to accept messages. The received data is recorded in memory or on disk and played back later, thus creating a multimedia message answering machine. In the message record mode, system delays are not limiting because the message does not have to be recorded in real time; the only requirement is to play it back in real time. The message is recorded on one machine, and sent as a complete message file to the other machine, and there stored on the drive.

A three way videoconference call is illustrated in FIG. 17. Caller 1, caller 2 and caller 3 are connected over an ethernet communication system. Each caller broadcasts multimedia digital packets to the other two callers. The connection may be expanded to more than three callers. Each caller will see a video image of all the other conferences on their screen in separate windows, as well as hear the conversation and view collaborative data.

An alternate embodiment for a three way videoconference call is illustrated in FIG. 18. Two callers (1 and 3) are on ethernet. Another caller, 2 is connected by modem. Caller 3 links caller 1 to caller 2. To link callers 1 and 2, caller 3 rebroadcasts received data packets from caller 1 over ethernet, to caller 2 over modem, and vice versa. 

1. In a communications network where a processing machine establishes communication between a first caller and a second caller, wherein said first caller is coupled to said processing machine over a first communication medium, and said processing machine is coupled to said second caller over a second communication medium, a method comprising: invoking at least one connection routine at said processing machine to cause control signals to be sent to at least one of said first and second callers to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted to at least one of said first and second callers, in accordance with said media type selections, over said first communication medium via one or more packet switched communication channels; and wherein for at least one of said at least two different media types, said processing machine causes media signals to be communicated between said first and second callers; and wherein said first communication medium comprises a packet switched network, and said second communication medium comprises a non-packet switched network.
 2. The method of claim 1, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 3. The method of claim 1, wherein said media signals communicated between said first and second callers are communicated between the packet switched network and a telephonic network.
 4. The method of claim 1, further comprising: assigning a priority to each of said plurality of digital media packets at said processing machine; wherein said plurality of digital media packets are transmitted from said processing machine in substantially the order of said assigned priorities.
 5. The method of claim 4, wherein said transmission of said plurality of digital media packets in substantially the order of said assigned priorities further comprises: providing a queue for holding said plurality of digital media packets prior to transmission; placing successive ones of said plurality of digital media packets in said queue in order of said assigned priorities; and transmitting a first digital media packet of said queue.
 6. The method of claim 1, wherein said plurality of digital media packets include video packets and audio packets.
 7. The method of claim 1, wherein said plurality of digital media packets include video packets, audio packets, and collaborative data packets.
 8. The method of claim 7, wherein said video packets are assigned a lower priority than said audio packets.
 9. The method of claim 7, wherein said collaborative data packets are assigned a lower priority than said video packets.
 10. The method of claim 1, wherein said media type selections are bidirectional media type selections.
 11. The method of claim 1, wherein a media type selection for said first caller is the same as a media type selection for said second caller.
 12. The method of claim 1, wherein a media type selection for said first caller is different than a media type selection for said second caller.
 13. The method of claim 1, wherein said second communication medium comprises a telephone line, and said second caller is coupled to the telephone line via a first modem.
 14. The method of claim 13, wherein said processing machine further comprises a second modem and communicating said media signals between said first and second callers comprises transmitting packets received from said first communication medium from said second modem to said first modem.
 15. The method of claim 1, wherein said act of causing control signals to be sent comprises sending messages from one or more connection routines at said processing machine to respective connection routines of the first and second callers.
 16. The method of claim 1, wherein said media type selections involve user interaction.
 17. In a communications network where a processing machine establishes communications between at least first and second user machines, said first user machine being coupled to said processing machine over a first communication medium, and said processing machine being coupled to said second user machine over a second communication medium, a method comprising: causing control signals to be sent to said first and second user machines to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types, said digital media packets being transmitted in accordance with said media type selections over said first communication medium; wherein for at least one of said at least two different media types, media signals are communicated between said first and second user machines; and wherein said first communication medium comprises a packet switched network, and said second communication medium comprises a non-packet switched network.
 18. The method of claim 17, wherein said first communication medium has an indeterminate packet loss.
 19. The method of claim 17, wherein said act of communicating media signals between said first and second user machines comprises communicating signals between the packet switched network and a telephonic network.
 20. The method of claim 17, wherein said act of communicating media signals between said first and second user machines comprises communicating signals between said first and second communication mediums.
 21. The method of claim 17, wherein the non-packet switched network comprises a telephone line.
 22. The method of claim 17, further comprising: assigning a priority to each of said plurality of digital media packets at said processing machine; wherein said plurality of digital media packets are transmitted from said processing machine in substantially the order of said assigned priorities.
 23. The method of claim 22, wherein said transmission of said plurality of digital media packets from said processing machine in substantially the order of said assigned priorities further comprises: providing a queue for holding said plurality of digital media packets prior to transmission; placing successive ones of said plurality of digital media packets in said queue in order of said assigned priorities; and transmitting a first digital media packet of said queue.
 24. The method of claim 17, wherein at least one of said media type selections is performed by a user.
 25. The method of claim 17, wherein at least one of said media type selections is self configured by a routine running on said first or second user machine.
 26. In a communications network where first and second user machines are adapted for communication with a processing machine via first and second communication mediums, respectively, a method of establishing user-to-user communication comprising: causing control signals to be sent to said first and second user machines to enable respective media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of packets corresponding to each of said at least two different media types, said plurality of packets being transmitted in accordance with said media type selections over at least one channel of said first communication medium; wherein for at least one of said at least two different media types, media signals are communicated between said first and second user machines via both said first and second communication mediums; and wherein said first communication medium comprises a packet switched network, and said second communication medium comprises a non-packet switched network.
 27. The method of claim 26, wherein said at least one channel has an indeterminate packet loss.
 28. The method of claim 26, wherein said act of communicating media signals between said first and second user machines comprises communicating between said packet switched network and a telephonic network.
 29. The method of claim 28, wherein said second user machine is coupled to the telephonic network via a first modem.
 30. The method of claim 29, wherein said processing machine further comprises a second modem, and said act of communicating media signals comprises transmitting packets received from said packet-switched network to said second user machine by transmitting said packets from the second modem to the first modem.
 31. The method of claim 26, wherein said causing control signals to be sent comprises sending messages from one or more connection routines in data communication with the processing machine to respective connection routines of the first and second user machines.
 32. For use in a system where an apparatus is adapted to communicate with a first caller via a packet switched network, communicate with a second caller at least via a telephone line, and to communicate signals between the first and second callers, a method comprising: negotiating with a remote processing machine a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the apparatus to process media data packets received from and to be transmitted to said remote processing machine over said packet switched network via one or more packet switched communication channels; and placing said second caller into signal communication with the apparatus at least via the telephone line; wherein said selection is of only audio, and said negotiation comprises sending a first message and receiving a response message, said negotiation involving a message format that supports the description of said audio, video and data media types, wherein the first message indicates that only audio is being offered in said negotiation; wherein the apparatus communicates information between said remote processing machine and said telephone line; and wherein the telephone line transmits and receives data in a non-packet switched manner.
 33. The method of claim 32, wherein said one or more packet switched communication channels has indeterminate packet loss, and wherein said indeterminate packet loss is at least in part a consequence of indeterminate system delays and bandwidth limitations of said one or more packet switched communications channels.
 34. The method of claim 32, further comprising: assigning a priority to each of said media data packets at said apparatus; wherein said media data packets are transmitted from said apparatus in substantially the order of said assigned priorities.
 35. The method of claim 34, wherein said transmission of said media data packets from said apparatus in substantially the order of said assigned priorities further comprises: providing a queue for holding said media data packets prior to transmission; placing successive ones of said media data packets in said queue in order of said assigned priority priorities; and transmitting a first media data packet of said queue.
 36. The method of claim 32, wherein said selection is a bidirectional media type selection.
 37. The method of claim 32, wherein said second caller is coupled to the telephone line via a first modem.
 38. The method of claim 37, wherein the apparatus further comprises a second modem and the communication of information comprises transmitting packets received from said packet switched network from the second modem to the first modem.
 39. The method of claim 32, wherein said negotiating comprises sending messages from one or more connection routines at the apparatus to a connection routine of the remote processing machine.
 40. The method of claim 32, wherein said remote processing machine is associated with the first caller.
 41. The method of claim 32, wherein said remote processing machine is coupled to said first caller via a second telephone line.
 42. The method of claim 41, wherein the first caller initiates said communication of signals between the first and second callers.
 43. The method of claim 41, wherein the second caller initiates said communication of signals between the first and second callers.
 44. A method of transmitting media data packets from a first processing machine to be delivered to one or more of a plurality of remote processing machines in data communication therewith, and for placing a telephone subscriber into communication with the plurality of remote processing machines, the method comprising: transmitting a plurality of media data packets for delivery to at least one of said plurality of remote processing machines over a packet switched network via one or more packet switched communication channels, said one or more packet switched communication channels having indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss, wherein each of said media data packets has a plurality of data fields associated therewith, at least one of said data fields comprising at least one destination address associated with a respective one of said plurality of remote processing machines; and communicating signals of at least one media type via a telephone network to couple the telephone subscriber into communication with the plurality of remote processing machines; wherein a first number of said plurality of media data packets may be transmitted for delivery to a first subset of said plurality of remote processing machines while a second number of said plurality of media data packets may be transmitted for delivery to a second subset of said plurality of remote processing machines, said first and second subsets not being identical.
 45. The method of claim 44, further comprising: receiving from at least one source of media data a plurality of media data; and formatting the plurality of media data to produce the plurality of media data packets.
 46. The method of claim 45, wherein the formatting comprises processing the plurality of media data to produce the plurality of media data packets.
 47. The method of claim 44, wherein the first subset involves remote processing machines which have negotiated the use of a first media type and the second subset involves remote processing machines which have negotiated the use of the first media type and a second media type.
 48. The method of claim 47, wherein the first media type corresponds to an audio media type, and the second media type corresponds to a video media type.
 49. The method of claim 47, wherein the first media type corresponds to an audio media type, and the second media type corresponds to a collaborative data media type.
 50. The method of claim 44, wherein said first subset comprises all of said plurality of remote processing machines, and said second subset comprises a lesser number thereof.
 51. The method of claim 44, further comprising generating, for each of said plurality of media data packets, a count of the number of said plurality of remote processing machines to which a respective media data packet of said plurality of media data packets was delivered, but not received.
 52. A method of operating an apparatus disposed in a telecommunications network, said apparatus comprising a computer readable medium having at least one computer program stored at least partly thereon, said at least one computer program being adapted to bridge into teleconferencing communication one or more of a plurality of remote processing machines that are in signal communication with said apparatus via a packet switched network, and a telephone subscriber coupled to the apparatus at least partially via a telephone line, the method comprising: transmitting a plurality of media data packets to at least one of said plurality of remote processing machines over said packet switched network via one or more packet switched communication channels, said one or more packet switched communication channels having indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss, wherein each of said media data packets has a plurality of data fields associated therewith, at least one of said data fields comprising at least one destination address associated with a respective one of said plurality of remote processing machines; and sending signals of at least one media type via a telephone network to couple said telephone subscriber into communication with the plurality of remote processing machines; wherein a first number of said plurality of media data packets may be transmitted for delivery to a first subset of said plurality of remote processing machines while a second number of said plurality of media data packets may be transmitted for delivery to a second subset of said plurality of remote processing machines, said first and second subsets not being identical.
 53. The method of claim 52, further comprising: receiving from at least one source of media data a plurality of media data; and formatting the plurality of media data to produce the plurality of media data packets.
 54. The method of claim 53, wherein the formatting comprises processing the plurality of media data to produce the plurality of media data packets.
 55. The method of claim 52, wherein said first subset comprises all of said plurality of remote processing machines, and said second subset comprises a lesser number thereof.
 56. The method of claim 52, wherein the first subset involves remote processing machines which have negotiated the use of a first media type and the second subset involves remote processing machines which have negotiated the use of the first media type and a second media type.
 57. The method of claim 56, wherein the first media type corresponds to an audio media type, and the second media type corresponds to a video media type.
 58. The method of claim 56, wherein the first media type corresponds to an audio media type, and the second media type corresponds to a collaborative data media type.
 59. The method of claim 52, further comprising generating, for each of said plurality of media data packets, a count of the number of said plurality of remote processing machines to which a respective media data packet of said plurality of media data packets was delivered, but not received.
 60. In a communications network where a first processing machine establishes communication between at least second and third processing machines, the second processing machine being in signal communication with said first processing machine via a first communication medium, said first processing machine being in signal communication with said third processing machine via a second communication medium, a method comprising: causing control signals to be sent to said second and third processing machines to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said first processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted via said first processing machine to at least one of said second and third processing machines consistent with said media type selections, said at least a portion of said plurality of corresponding digital media packets being transmitted over said first communication medium via one or more packet switched communication channels; wherein for at least one of said at least two different media types, the first processing machine causes media signals to be communicated between the second and third processing machines; and wherein said first communication medium comprises a packet switched network, and said second communication medium comprises a non-packet switched network.
 61. The method of claim 60, wherein said communication of media signals comprises communication of packetized media data.
 62. The method of claim 60, wherein said one or more packet switched communication channels have an indeterminate packet loss.
 63. The method of claim 60, wherein said at least one of said at least two different media types comprises two media types.
 64. The method of claim 60, wherein said at least one of said at least two different media types comprises all of said at least two media types.
 65. In a communications network where a processing machine establishes communication between at least first and second users, said first user being in signal communication with said processing machine via a first communication medium, said processing machine being in signal communication with said second user via a second communication medium, a method comprising: causing control signals to be sent to at least one of said first and second users to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted via said processing machine to at least one of said first and second users consistent with said media type selections, said at least a portion of said plurality of corresponding digital media packets being transmitted over said first communication medium via one or more packet switched communication channels; wherein for at least one of said at least two different media types, said processing machine causes media signals to be communicated between said first and second users, and wherein one of said first and second communication mediums comprises a packet switched network, and the other of said first and second communication mediums comprises a non-packet switched network.
 66. In a communications network where a first processing machine establishes communication between at least second and third processing machines, said second processing machine being in communication with said first processing machine via a packet-switched network having an indeterminate packet loss, said first processing machine being in signal communication with said third processing machine via at least a non-packet switched network, a method comprising: causing control signals to be sent to said second and third processing machines to enable media type selections at each said second and third processing machines, at least said media type selection of said second processing machine comprising a selection of at least two different media types; and transmitting via said first processing machine and said packet-switched network a plurality of digital media packets corresponding to each of said at least two different media types selected at said second processing machine; wherein, for at least one of said at least two different media types, at least a portion of said transmitted digital media packets are also transmitted for delivery to at least said third processing machine consistent with said third processing machine's media type selection, said first processing machine causing media signals related to said at least a portion of said transmitted digital media packets to be communicated to said third processing machine.
 67. The method of claim 66, wherein said communication of said media signals to said third processing machine comprises communicating digital media packets.
 68. In a communications network where a first processing machine establishes communication between at least second and third processing machines, the second processing machine being in communication with said first processing machine via communications channels of a packet-switched network having indeterminate packet loss, said first processing machine being in signal communication with said third processing machine via at least a non-packet switched network, a method comprising: causing control signals to be sent to said second and third processing machines to enable media type selections; and transmitting via said first processing machine and said communications channels a plurality of digital media packets corresponding to each of at least two different media types selected via said second processing machine based at least in part on said control signals; wherein, for at least one of said at least two different media types, said first processing machine further causes signals related to at least a portion of said transmitted digital media packets to be delivered to at least said third processing machine consistent with said third processing machine's media type selection.
 69. In a communications network where a processing machine establishes communication between at least first and second users, said first user being in communication with said processing machine via a packet-switched network having an indeterminate packet loss, said first processing machine being in signal communication with said second user via at least a non-packet switched network, a method comprising: causing control signals to be sent to at least one of said first and second users to enable respective media type selections; and transmitting via said processing machine and said packet-switched network a plurality of digital media packets corresponding to each of at least two different first user media types, said at least two different first user media types being selected based at least in part on said control signals; wherein, for at least one of said at least two different first user media types, said first processing machine further causes signals associated with at least a portion of said plurality of digital media packets to be delivered to at least said second user consistent with said second user media type selection.
 70. For use in a system where a communications apparatus is adapted to communicate with a first caller apparatus over a packet switched network and with a second caller apparatus via a telephone line, and to communicate signals between the first and second caller apparatus, a method comprising: negotiating with the first caller apparatus a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the communication apparatus to process media data packets received from and to be transmitted to said first caller apparatus over said packet switched network via one or more packet switched communication channels having indeterminate packet loss; and placing said second caller apparatus into signal communication with the communication apparatus at least via the telephone line; wherein said selection is of only audio, and said negotiation comprises sending a first message and receiving a response message, said negotiation involving a message format that supports the description of the audio, video and data media types, wherein the first message indicates that only audio is being offered in the present negotiation; and wherein the communication apparatus communicates information between said first caller apparatus and said telephone line.
 71. For use in an apparatus adapted to couple into communication a remote processing machine with a caller coupled via a telephone line, a method comprising: negotiating with said remote processing machine a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the apparatus to process media data packets received from and to be transmitted to said remote processing machine over a packet switched network via one or more packet switched communication channels, said one or more packet switched communication channels having indeterminate packet loss; and placing said caller into signal communication with the apparatus at least via the telephone line; wherein said selection is of only audio, and said negotiation comprises sending a first message and receiving a response message, said negotiation involving a message format that supports the description of the audio, video and data media types; and wherein the apparatus communicates information between said remote processing machine and said telephone line.
 72. The method of claim 71, wherein said indeterminate packet loss is determined at least in part by indeterminate system delays and bandwidth limitations of said packet switched communications channels.
 73. The method of claim 71, further comprising: assigning a priority to each of said media data packets at said apparatus; wherein said media data packets are transmitted from said apparatus in substantially the order of said assigned priorities.
 74. The method of claim 73, wherein said transmission of said media data packets from said apparatus in substantially the order of said assigned priorities further comprises: providing a queue for holding said media data packets prior to transmission; placing successive ones of said media data packets in said queue in order of said assigned priorities; and transmitting a first media data packet of said queue.
 75. The method of claim 71, wherein the selection is a bidirectional media type selection.
 76. The method of claim 71, wherein said caller is coupled to the telephone line via a first modem.
 77. The method of claim 76, wherein the apparatus further comprises a second modem and the act of communicating information comprises transmitting media data packets received from the packet switched network from the second modem to the first modem.
 78. The method of claim 71, wherein said act of negotiating comprises sending messages from one or more connection routines at the apparatus to a connection routine of the remote processing machine.
 79. The method of claim 71, wherein said remote processing machine is associated with another caller.
 80. The method of claim 79, wherein said remote processing machine is coupled to said another caller via a second telephone line.
 81. The method of claim 80, wherein said caller initiates communication.
 82. The method of claim 80, wherein said another caller initiates communication.
 83. For use in an apparatus adapted to couple into communication a remote processing machine with a caller coupled via a telephone line, a method comprising: negotiating with said remote processing machine a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the apparatus to process media data packets received from and to be transmitted to said remote processing machine over a packet switched network; and placing said caller into signal communication with the apparatus at least via the telephone line; wherein said selection is of only audio, and said negotiation comprises a message format that supports the description of the audio, video and data media types; and wherein the apparatus communicates information between said remote processing machine and said telephone line.
 84. The method of claim 83, wherein said packet switched network introduces indeterminate packet loss determined at least in part by indeterminate system delays and bandwidth limitations of said packet switched network.
 85. The method of claim 83, further comprising: assigning a priority to each of said media data packets at said apparatus; wherein said media data packets are transmitted from said apparatus in substantially the order of said assigned priorities.
 86. The method of claim 85, wherein said transmission of said media data packets from said apparatus in substantially the order of said assigned priorities further comprises: providing a queue for holding said media data packets prior to transmission; placing successive ones of said media data packets in said queue in order of said assigned priorities; and transmitting a first media data packet of said queue.
 87. The method of claim 83, wherein said media type selection is a bidirectional media type selection.
 88. The method of claim 83, wherein said caller is coupled to the telephone line via a first modem.
 89. The method of claim 88, wherein the apparatus further comprises a second modem and the act of communicating information comprises transmitting media data packets received from the packet switched network from the second modem to the first modem.
 90. The method of claim 83, wherein said act of negotiating comprises sending messages from one or more connection routines at the apparatus to a connection routine of the remote processing machine.
 91. The method of claim 83, wherein said remote processing machine is associated with a second caller.
 92. The method of claim 91, wherein said remote processing machine is coupled to said second caller via a second telephone line.
 93. The method of claim 92, wherein said caller initiates communication.
 94. The method of claim 92, wherein said second caller initiates communication.
 95. For use in an apparatus adapted to couple into communication a remote processing means with a caller coupled via a telephonic means, a method comprising the steps of: a step for negotiating with said remote processing means a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the apparatus to process media data packets received from and to be transmitted to said remote processing means over a packet switched network; a step for placing said caller into signal communication with the apparatus at least via the telephonic means; wherein said selection is of only audio, and said negotiation comprises a message format that supports the description of the audio, video and data media types; and a step for the apparatus to communicate information between said remote processing means and said telephonic means.
 96. The method as claimed in claim 95, wherein the packet switched network introduces indeterminate packet loss.
 97. In a communications network where a processing machine establishes communication between at least a first caller, a second caller, and a third caller, wherein said first caller is coupled to said processing machine over a first communication medium, and said processing machine is coupled to said second caller over a second communication medium, and said processing machine is coupled to said third caller over a third communication medium, a method comprising: invoking at least one connection routine at said processing machine to cause control signals to be sent to at least one of said first, second and third callers to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted to at least one of said first, second and third callers, in accordance with said media type selections, over said first communication medium via one or more packet switched communication channels; wherein for at least one of said at least two different media types, the processing machine causes media signals to be communicated among the first, second and third callers; and wherein in at least one supported mode of communication, a first number of said plurality of digital media packets is transmitted for delivery from said first caller to said second caller while a second number of said plurality of digital media packets is transmitted for delivery from said first caller to said third caller, wherein said first and second numbers may not be identical.
 98. The method as claimed in claim 97, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 99. The method as claimed in claim 97, wherein at least one of said media type selections is performed by either a user or by a routine running on a device used by said user.
 100. The method as claimed in claim 97, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 101. In a communications network where a processing machine establishes communications between at least first, second and third user machines, said first user machine being coupled to said processing machine over a first communication medium, said processing machine being coupled to said second user machine over a second communication medium, said processing machine being coupled to said third user machine over a third communication medium, a method comprising: causing control signals to be sent to said first, second and third user machines to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types, said plurality of digital media packets being transmitted in accordance with said media type selections over said first communication medium via one or more packet switched communication channels; wherein for at least one of said at least two different media types, media signals are communicated among said first, second and third user machines; and wherein in at least one supported mode of communication, a first number of said plurality of digital media packets is transmitted for delivery from said first user machine to said second user machine while a second number of said plurality of digital media packets is transmitted for delivery from said first user machine to said third user machine, wherein said first and second numbers may not be identical.
 102. The method as claimed in claim 101, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 103. The method as claimed in claim 101, wherein at least one of said media type selections is performed by either a user or by a routine running on at least one of said first, second and third user machines.
 104. The method as claimed in claim 101, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 105. For use in a system where a processing machine is adapted to communicate with a first caller via a packet switched network, communicate with a second caller at least via a second network, communicate with a third caller at least via a third network, and to communicate signals among the first, second and third callers, a method comprising: negotiating with a remote processing machine a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the processing machine to process media data packets received from and to be transmitted to said remote processing machine over said packet switched network via one or more packet switched communication channels; placing said second caller into signal communication with the processing machine at least via the second network; and placing said third caller into signal communication with the processing machine at least via the third network; wherein said selection is of only audio, and said negotiation comprises sending a first message and receiving a response message, said negotiation involving a message format that supports the description of the audio, video and data media types, wherein the first message indicates that only audio is being offered in the negotiation; and wherein in at least one supported mode of communication, a first number of said media data packets is transmitted for delivery from said first caller to said second caller while a second number of said media data packets is transmitted for delivery from said first caller to said third caller, wherein said first and second numbers may not be identical.
 106. The method as claimed in claim 105, wherein said media data packets include video packets, audio packets, and collaborative data packets.
 107. The method as claimed in claim 105, wherein said selection is performed by either a user or by a routine running on a device used by said user.
 108. The method as claimed in claim 105, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 109. In a communications network where a first processing machine establishes communication between at least second and third processing machines, said second processing machine being in signal communication with said first processing machine via a first communication medium, said first processing machine being in signal communication with said third processing machine via a second communication medium, a method comprising: causing control signals to be sent to said second and third processing machines to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said first processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted via said first processing machine to at least one of said second and third processing machines consistent with said media type selections, said at least a portion of said plurality of corresponding digital media packets being transmitted over said first communication medium via one or more packet switched communication channels; wherein for at least one of said at least two different media types, the first processing machine causes media signals to be communicated between the second and third processing machines; and wherein in at least one supported mode of communication, a first number of said plurality of digital media packets is transmitted for delivery from said first processing machine to said second processing machine while a second number of said plurality of digital media packets is transmitted for delivery from said first processing machine to said third processing machine, wherein said first and second numbers may not be identical.
 110. The method as claimed in claim 109, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 111. The method as claimed in claim 109, wherein at least one of said media type selections is performed by either a user or by a routine running on at least one of said first, second and third processing machines.
 112. The method as claimed in claim 109, wherein said one or more packet switched communication channels providing provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 113. In a communications network where a processing machine establishes communication between at least first, second and third users, said first user being in signal communication with said processing machine via a first communication medium, said processing machine being in signal communication with said second user via a second communication medium, said processing machine being in signal communication with said third user via a third communication medium, a method comprising: causing control signals to be sent to at least one of said first, second and third users to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted via said processing machine to at least one of said first, second and third users consistent with said media type selections, said at least a portion of said plurality of corresponding digital media packets being transmitted over said first communication medium via one or more packet switched communication channels; wherein for at least one of said at least two different media types, said processing machine causes media signals to be communicated among said first, second and third users; and wherein in at least one supported mode of communication, a first number of said plurality of digital media packets is transmitted for delivery from said first user to said second user while a second number of said plurality of digital media packets is transmitted for delivery from said first user to said third user, wherein said first and second numbers may not be identical.
 114. The method as claimed in claim 113, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 115. The method as claimed in claim 113, wherein at least one of said media type selections is performed by either a user or by a routine running on a machine used by said user.
 116. The method as claimed in claim 113, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 117. In a communications network where a processing machine establishes communication between a first caller and a second caller, wherein said first caller is coupled to said processing machine over a first communication medium, and said processing machine is coupled to said second caller over a second communication medium, a method comprising: invoking at least one connection routine at said processing machine to cause control signals to be sent to at least one of said first and second callers to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted to at least one of said first and second callers in accordance with said media type selections over said first communication medium via one or more packet switched communication channels, said one or more packet switched communication channels including a single connection stream that includes packets of at least one media stream set up for each of said media type selections by said first and second callers; and wherein for at least one of said at least two different media types, the processing machine causes media signals to be communicated between the first and second callers.
 118. The method as claimed in claim 117, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 119. The method as claimed in claim 117, wherein at least one of said media type selections is performed by either a user or by a routine running on a machine used by said user.
 120. The method as claimed in claim 117, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 121. In a communications network where a processing machine establishes communications between at least first and second user machines, said first user machine being coupled to said processing machine over a first communication medium, and said processing machine being coupled to said second user machine over a second communication medium, a method comprising: causing control signals to be sent to said first and second user machines to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types, said plurality of digital media packets being transmitted in accordance with said media type selections over said first communication medium via one or more packet switched communication channels, said one or more packet switched communication channels including a single connection stream that includes packets of at least one media stream set up for each of said media type selections; wherein for at least one of said at least two different media types, media signals are communicated between the first and second user machines.
 122. The method as claimed in claim 121, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 123. The method as claimed in claim 121, wherein at least one of said media type selections is performed by either a user or by a routine running on at least one of said first or second user machines.
 124. The method as claimed in claim 121, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 125. In a communications network where first and second user machines are adapted for communication with a processing machine via first and second communication mediums, respectively, a method of establishing user-to-user communication comprising: causing control signals to be sent to said first and second user machines to enable respective media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of packets corresponding to each of said at least two different media types, said packets being transmitted in accordance with said media type selections over at least one channel of said first medium, said at least one channel including a single connection stream that includes packets of at least one media stream set up for each of said at least two different media types; wherein for at least one of said at least two different media types, media signals are communicated between the first and second user machines via both said first and second communication mediums.
 126. The method as claimed in claim 125, wherein said packets include video packets, audio packets, and collaborative data packets.
 127. The method as claimed in claim 125, wherein at least one of said media type selections is performed by either a user or by a routine running on at least one of said first and second user machines.
 128. The method as claimed in claim 125, wherein said at least one channel provides indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 129. For use in a system where a processing machine is adapted to communicate with a first caller via a packet switched network, communicate with a second caller at least via a telephone line, and to communicate signals between the first and second callers, a method comprising: negotiating with a remote processing machine a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the processing machine to process media data packets received from and to be transmitted to said remote processing machine over said packet switched network via one or more packet switched communication channels, said one or more packet switched communication channels including a single connection stream that includes packets of at least one media stream set up for each of said at least one media type; and placing said second caller into signal communication with the processing machine at least via the telephone line; wherein said selection is of only audio, and said negotiation comprises sending a first message and receiving a response message, said negotiation involving a message format that supports the description of the audio, video and data media types, wherein the first message indicates that only audio is being offered in the negotiation; and wherein the processing machine communicates information between said remote processing machine and said telephone line.
 130. The method as claimed in claim 129, wherein said media data packets include video packets, audio packets, and collaborative data packets.
 131. The method as claimed in claim 129, wherein said selection is performed by either a user or by a routine running on at least one of said remote processing machine and said telephone line.
 132. The method as claimed in claim 129, wherein said one or more communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 133. In a communications network where a first processing machine establishes communication between at least second and third processing machines, the second processing machine being in signal communication with said first processing machine via a first communication medium, said first processing machine being in signal communication with said third processing machine via a second communication medium, a method comprising: causing control signals to be sent to said second and third processing machines to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said first processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted via said first processing machine to at least one of said second and third processing machines consistent with said media type selections, said at least a portion of said plurality of corresponding digital media packets being transmitted over said first communication medium via one or more packet switched communication channels, said one or more packet switched communication channels including a single connection stream that includes packets of at least one media stream set up for each of said at least two different media types; and wherein for at least one of said at least two different media types, the first processing machine causes media signals to be communicated between the second and third processing machines.
 134. The method as claimed in claim 133, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 135. The method as claimed in claim 133, wherein at least one of said media type selections is performed by either a user or by a routine running on at least one of said first, second and third processing machines.
 136. The method as claimed in claim 133, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 137. In a communications network where a processing machine establishes communication between at least first and second users, the first user being in signal communication with said processing machine via a first communication medium, said processing machine being in signal communication with said second user via a second communication medium, a method comprising: causing control signals to be sent to at least one of said first and second users to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted via said processing machine to at least one of said first and second users consistent with said media type selections, said at least a portion of said plurality of corresponding digital media packets being transmitted over said first communication medium via one or more packet switched communication channels, said one or more packet switched communication channels including a single connection stream that includes packets of at least one media stream set up for each of said at least two different media types; and wherein for at least one of said at least two different media types, the processing machine causes media signals to be communicated between the first and second users.
 138. The method as claimed in claim 137, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 139. The method as claimed in claim 137, wherein at least one of said media type selections is performed by either a user or by a routine running on a machine used by said user.
 140. The method as claimed in claim 137, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 141. For use in a system where a processing machine is adapted to communicate with a first caller via a first network that corresponds to a packet switched network, communicate with a second caller at least via a second network, and to communicate signals between the first and second callers, a method comprising: negotiating with a remote processing machine a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the processing machine to process media data packets received from and to be transmitted to said remote processing machine over said packet switched network via one or more packet switched communication channels; placing said second caller into signal communication with the processing machine at least via the second network; wherein, in a case where the second network is a telephone line and said selection is of only audio, said negotiation comprises sending a first message and receiving a response message, said negotiation involving a message format that supports the description of the audio, video and data media types, wherein the response message indicates that only audio is being accepted in the negotiation; and wherein the processing machine communicates information between said remote processing machine and said second network.
 142. The method as claimed in claim 141, wherein said media data packets include video packets, audio packets, and collaborative data packets.
 143. The method as claimed in claim 141, wherein said selection is performed by either a user or by a routine running on a machine used by said user.
 144. The method as claimed in claim 141, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 145. In a communications network where a processing machine establishes communication between a first caller and a second caller, wherein said first caller is coupled to said processing machine over a first communication medium, and said processing machine is coupled to said second caller over a second communication medium, a method comprising: invoking at least one connection routine at said processing machine to cause control signals to be sent to at least one of said first and second callers to enable media type selections, at least one of said media type selections including a selection of at least two different media types; and transmitting via said processing machine a plurality of digital media packets corresponding to each of said at least two different media types; wherein, for at least one of said at least two different media types, at least a portion of said plurality of corresponding digital media packets are transmitted to at least one of said first and second callers, in accordance with said media type selections, over said first communication medium via one or more packet switched communication channels, wherein for at least one of said at least two different media types, the processing machine causes media signals to be communicated between the first and second callers, and wherein said processing machine is adapted to assign a priority to each of said corresponding digital media packets, said method further comprising: holding, in a queue, said plurality of corresponding digital media packets prior to transmission; placing successive ones of said plurality of corresponding digital media packets in said queue in order of said assigned priorities; and transmitting a first digital media packet in said queue.
 146. The method as claimed in claim 145, wherein said digital media packets include video packets, audio packets, and collaborative data packets.
 147. The method as claimed in claim 145, wherein at least one of said media type selections is performed by either a user or by a routine running on a machine used by said user.
 148. The method as claimed in claim 145, wherein said one or more packet switched communication channels provide indeterminate system delays and bandwidth limitations that give rise to indeterminate packet loss.
 149. A method of transmitting data packets from a first processing machine to be delivered to one or more of a plurality of remote processing machines in data communication therewith, and for placing a telephone subscriber into communication with the plurality of remote processing machines, the method comprising: transmitting a plurality of media data packets for delivery to at least one of said plurality of remote processing machines over a packet switched network via one or more packet switched communication channels, wherein each of said media data packets has a plurality of data fields associated therewith, at least one of said data fields comprising at least one destination address associated with a respective one of said plurality of remote processing machines; and communicating signals of at least one media type via a telephone network to couple the telephone subscriber into communication with the plurality of remote processing machines; wherein a first number of said plurality of media data packets may be transmitted for delivery to a first subset of said plurality of remote processing machines while a second number of said plurality of media data packets may be transmitted for delivery to a second subset of said plurality of remote processing machines, said first and second subsets not being identical.
 150. A method of operating an apparatus disposed in a telecommunications network, said apparatus comprising a computer readable medium having at least one computer program stored at least partly thereon, said at least one computer program being adapted to bridge into teleconferencing communication one or more of a plurality of remote processing machines that are in signal communication with said apparatus via a packet switched network, and a telephone subscriber coupled to the apparatus at least partially via a telephone line, the method comprising: transmitting each of a plurality of media data packets to at least one of said plurality of remote processing machines over said packet switched network via one or more packet switched communication channels, wherein each of said media data packets has a plurality of data fields associated therewith, at least one of said data fields comprising at least one destination address associated with a respective one of said plurality of remote processing machines; and sending signals of at least one media type via a telephone network to couple said telephone subscriber into communication with the plurality of remote processing machines; wherein a first number of said plurality of media data packets may be transmitted for delivery to a first subset of said plurality of remote processing machines while a second number of said plurality of packets may be transmitted for delivery to a second subset of said plurality of remote processing machines, said first and second subsets not being identical.
 151. For use in an apparatus adapted to couple into communication a remote processing machine with a caller coupled via a telephone line, a method comprising: negotiating with said remote processing machine a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the apparatus to process media data packets received from and to be transmitted to said remote processing machine over a packet switched network via one or more packet switched communication channels; and placing said caller into signal communication with the apparatus at least via the telephone line; wherein said selection is of only audio, and said negotiation comprises sending a first message and receiving a response message, said negotiation involving a message format that supports the description of the audio, video and data media types; and wherein the apparatus communicates information between said remote processing machine and said telephone line.
 152. For use in an apparatus adapted to couple into communication a remote processing means with a caller coupled via a telephonic means, a method comprising the steps of: a step for negotiating with said remote processing means a selection of at least one media type from a plurality of media types including audio, video and data, and to configure, according to said selection, the apparatus to process media data packets received from and to be transmitted to said remote processing means over a packet switched network; a step for placing said caller into signal communication with the apparatus at least via the telephonic means; wherein said selection is of only audio, and said negotiation comprises a message format that supports the description of the audio, video and data media types; and a step for the apparatus to communicate information between said remote processing means and said telephonic means. 